Lack of association between p53 expression and betel nut chewing in oral cancers from Thailand.

To elucidate whether betel-associated oral squamous cell carcinoma is associated with p53 protein expression, tumor samples from 156 patients with detailed histories of exposures were investigated immunohistochemically using CM1 antibody. The expression of p53 (>10% positive cells) was found in 38.5% of the cases. The frequency of expression in betel chewers alone and betel chewer with tobacco use were 37.9% (11/29) and 25%(9/36), respectively, whereas that in betel chewers with smoking/drinking it was 47.2%(17/36) and in smokers or drinkers without chewing was 42.0% (21/50). However, the differences were not statistically significant. Multivariate analysis also revealed with the no independent association of betel chewing with p53 expression (odds ratio [OR] 1.81, 95% confidence interval 0.50-6.49), whereas alcohol drinking and smokeless tobacco use were significant (OR 7.58, 2.01-28.53 and 0.39, 0.16-0.98, respectively). These results suggested that betel chewing with or without smokeless tobacco use may not induce oral cancers via a p53-dependent pathway. However, since this is an immunohistochemical study, further molecular analysis is needed.

Lack of carcinogenicity of tragacanth gum in B6C3F1 mice.

Tragacanth gum was administered at dietary levels of 0 (control), 1.25 and 5.0% to groups of 50 male and 50 female B6C3F1 mice for 96 wk after which all animals were maintained on a basal diet without tragacanth gum for a further 10 wk. Mean body weights of females in the 5.0% and 1.25% groups were lower than those of the controls after 11 and 16 wk, respectively. However, there were no treatment-related clinical signs or adverse effects on survival rate, urinalysis, haematology, blood biochemistry and organ weight. While detailed histopathology revealed the development of squamous cell hyperplasias, papillomas and one carcinoma in the forestomach, there was no significant treatment-related increase in the incidence of any preneoplastic or neoplastic lesion. Thus, under the experimental conditions used, tragacanth gum was not carcinogenic in B6C3F1 mice of either sex.

Precancerous lesion and early carcinoma of the pyriform sinus.

Thirty-five specimens from total laryngopharyngectomy clinically diagnosed as squamous cell carcinoma of the pyriform sinus were studied. Patients receiving chemotherapy or radiotherapy were excluded. Pathological examinations revealed 26 (74.3%) precancerous lesions and early carcinoma of the pyriform sinus. Eight out of 26 cases were detected by gross examination. Most pathological findings were carcinoma in situ (CIS). Epithelial changes of the pyriform sinus were not similar to those of the uterine cervix. They usually showed abrupt change, frequently from normal to CIS, mild dysplasia to invasive carcinoma and these lesions can be detected early by physical examination. Because of multifoci of carcinoma, the concept of "multicentric origin" is proposed.

Hematoxylin-lac-curcuma polychrome stain for mucin.

A polychrome method for detection of mucin substance in paraffin section is produced by sequential stepwise staining of hematoxylin, crude lac extract (Laccifer lacca), and crude curcuma extract (khamin shan-Curcuma longa). The name LacCur stain is proposed. After a tissue section is deparaffinized and rehydrated, it is stained with Weigert's hematoxylin for 7 minutes. After a quick wash, it is stained for at least 3 hours with lac dye mordanted with aluminum chloride. Washed again and premordanted with ferric chloride for 1 minute, in the last step, it is counterstained with curcuma dye for 5 minutes. With this staining method, the nuclei are stained black, mucin deep red, and organelles and ground substances brownish yellow. The method and outcome colors are comparable to the widely used Mayer's mucicarmine staining method. It costs less than the Mayer's mucicarmine staining method and the procedure is not complicated.

p53 protein expression in cutaneous squamous cell carcinoma.

BACKGROUND: p53 is a nucleoprotein encoded by a tumor suppressor gene. It's mutations are implicated in the genesis of a wide variety of malignant neoplasia including skin cancers. OBJECTIVE: To study the expression of the p53 protein in cutaneous squamous cell carcinoma (SCCs) and evaluate the relationships between this expression and sites, varying degrees of differentiation and amounts of apoptotic cells. METHOD: Sixty-seven tissue samples of SCCs from Songklanagarind Hospital obtained from January 1991 to December 1996 were examined by immunohistochemistry using polyclonal anti p53-CM1. (Novocastra Laboratories, Newcastle, England, dilution 1:700) RESULT: p53 Immunoreactivity was demonstrated in 26.87 per cent of SCCs. This was observed in 15/51 of sun-exposed cases and 3/16 of sun-protected cases (p = 0.401). The more differentiated the tumor, the less p53 staining was observed (p = 0.043). There was no association between p53 positivity and the amounts of apoptotic cells. CONCLUSION: The p53 expression is not related to the sun exposure. It does not represent a commitment to apoptosis. However, it may indicate the differentiation and/or proliferative status of the tumor cells.

p53 expression related to the aggressive infiltrative histopathological feature of basal cell carcinoma.

AIMS: To determine whether the p53 protein expression which is involved in the genesis and progression of various malignant tumours may relate to age, sites or the aggressive histopathological feature of the basal cell carcinoma. METHODS ADN RESULTS: One hundred and fifty-eight basal cell carcinoma specimens from Songklanakarind Hospital, southern Thailand, collected from January 1992 to December 2000, were examined by immunohistochemistry using polyclonal anti-p53-CM1 (Novocastra Laboratories, Newcastle, UK; dilution 1:700). p53 protein expression was demonstrated in 48.7% of cases. The multivariate analysis showed that the aggressive infiltrative histopathological type was significantly associated with p53 expression (odds ratio 2.95, 95% confidence interval 1.10-7.90), whereas age, sun-exposure site, cellular response and fibrosis were not. CONCLUSIONS: The p53 expression is found to be related to the aggressive histopathological feature, which may be of predictive value for the behaviour of basal cell carcinoma. However, this result does not support the relation between sun exposure inducing basal cell carcinoma and p53 protein expression.

Enhancing effect of concomitant L-ascorbic acid administration on BHA-induced forestomach carcinogenesis in rats.

The effects of the synthetic antioxidant butylated hydroxyanisole (BHA) and naturally occurring antioxidants such as L-ascorbic acid (AsA; vitamin C), citric acid, benzoic acid or gallic acid in combination, on the development of rat forestomach epithelial lesions were investigated. A dietary level of 2.0% was selected for all antioxidants and the experimental period was 1 year. As compared with BHA alone, treatment with AsA in combination with BHA increased the severity of the hyperplasia in the mid-region, but not in the prefundic region of the forestomach epithelium, as well as the multiplicity of forestomach tumors. Furthermore, incidences of squamous cell carcinomas (SCCs) in the forestomach were significantly elevated in this group, while papilloma development only showed a tendency to increase. In addition, SCC invasion into the muscle layer of the forestomach was observed only in the BHA + AsA group. Treatment with the other antioxidants did not affect BHA-induced forestomach lesion development. The present study demonstrated that AsA can clearly enhance BHA forestomach carcinogenesis.

Stage and organ dependent effects of 1-O-hexyl-2,3,5-trimethylhydroquinone, ascorbic acid derivatives, n-heptadecane-8-10-dione and phenylethyl isothiocyanate in a rat multiorgan carcinogenesis model.

The effects of 1-O-hexyl-2,3,5-trimethylhydroquinone (HTHQ), phenylethylisothiocyanate (PEITC), 3-O-ethylascorbic acid, 3-O-dodecylcarbomethylascorbic acid and n-heptadecane-8, 10-dione were analyzed in a rat multiorgan carcinogenesis model. Groups of 15 animals were given a single intraperitoneal (i.p.) injection of diethylnitrosamine and 4 i.p. injections of N-methylnitrosourea as well as N-butyl-N-(4-hydroxybutyl) nitrosamine in the drinking water during the first 2 weeks. Then 4 subcutaneous (s.c.) injections of dimethylhydrazine and 2,2'-dihydroxy-di-n-propylnitrosamine were given in the drinking water over the next 2 weeks for initiation. Test compounds were administered during the initiation or post-initiation periods. The dietary dose was 1% except for n-heptadecane-8, 10-dione and PEITC (0.1%). Complete autopsy was performed at the end of experimental week 28. All 5 compounds reduced the number of lung hyperplasia, particularly PEITC when given during the initiation period. In addition, HTHQ lowered the incidence of esophageal hyperplasia in the initiation period, and of small and large intestinal adenomas in the post-initiation period. However, it also enhanced the development of hyperplasia and papilloma in the forestomach and tongue. PEITC lowered the induction of esophageal hyperplasia, kidney atypical tubules and liver glutathione S-transferase placental form (GST-P)-positive foci when given during the initiation period but enhanced the development of liver GST-P positive foci and urinary bladder tumors in the post-initiation period. Moreover, it induced hyperplasia of the urinary bladder. Our results indicate minor adverse effects for HTHQ in the forestomach and tongue, and demonstrate that PEITC, which inhibits carcinogenesis at the initiation stage in several organs, also exhibits promotion potential in liver and urinary bladder in the post-initiation stage under the present experimental conditions.

Dose dependence of 1-O-hexyl-2,3,5-trimethylhydroquinone promotion of forestomach carcinogenesis in rats pretreated with N-ethylnitrosourethane.

Post-initiation dose-dependent effects of the chemopreventive antioxidant 1-O-hexyl-2, 3, 5-trimethylhydroquinone (HTHQ), a potent inhibitor of heterocyclic amine-induced mutagenesis and carcinogenesis, on the development of forestomach and tongue tumors were investigated in male F344 rats. Groups of 22 rats were treated with 0.01% ethylnitrosourethane (ENUR) as an initiator in the drinking water for 4 weeks, then placed on diet containing 1.0%, 0.5%, 0.25% or 0.125% HTHQ, or basal diet alone for 36 weeks. Further group of 12 rats each were similarly treated with the different doses of HTHQ or given basal diet alone for 36 weeks without prior ENUR treatment. All animals were killed at week 40. Tongue papillary hyperplasia and papillomas tended to be increased in the groups treated with ENUR followed by 0.5-0.125% HTHQ, though there was no effect at the highest dose, in line with increased bromodeoxyuridine labeling indices. In the forestomach, the incidences of papillomas and carcinomas were also significantly elevated only in the group treated with ENUR followed by 0.125% HTHQ. Without ENUR pretreatment, papillary hyperplasia was found in the 1-0.125% HTHQ groups and the labeling index was also increased, though without clear dose dependence. The results indicate that HTHQ may have very weak or weak promotion potential for tongue and forestomach carcinogenesis, but that both minimum and maximum thresholds for active dose levels may exist.

Electron microscopic study of liver tissue from 30 thalassemic patients.

Electron microscopic study of liver tissue from 30 thal patients in advanced stages has been described. In all cases, regardless of the type of hemoglobin, electron microscopic observations gave identical results. Significant findings are ferroacidophilic bodies, ferroacidophilic degeneration of hepatocytes, interhepatocyte collagen, hemosiderin and ferritin, paracrystalline accumulations of ferritin molecules, and liver cell ballooning. The ultrastructures of FAB, FAD, and balloon cells were similar to those seen in viral hepatitis, but no viral particles were found.

Carcinogenic potential of some pesticides in a medium-term multi-organ bioassay in rats.

The carcinogenic potential of 5 pesticides was analyzed using a medium-term multi-organ bioassay for carcinogenicity. Male F344 rats were initially treated with 3 known carcinogens (diethylnitrosamine, N-methyl-N-nitrosourea and N-bis(2-hydroxypropyl)nitrosamine) during a period of 4 weeks to induce neoplastic changes in a variety of organs, and then given one of 5 pesticides in the diet for a further 16 weeks. Neoplastic and pre-neoplastic lesions were found in the thyroid, kidney and urinary bladder with propineb, in the forestomach, kidney and thyroid with captan and folpet. The number of glutathione S-transferase placental-form-positive liver-cell foci was significantly increased in the captan- and phosmet-treated groups. Based on these findings, captan and propineb can be considered as carcinogens and carcinogenicity is suspected for folpet and phosmet. These results are in concordance with reported long-term carcinogenicity for captan, folpet and propineb. Daminozide was considered not to be carcinogenic. Thus, the present assay of 20 weeks' duration is useful for the prediction of potential carcinogens.

Inhibitory effect of chlorophyllin on PhIP-induced mammary carcinogenesis in female F344 rats.

Chlorophyll and chlorophyllin, a water-soluble salt of chlorophyll, have been reported to inhibit carcinogen-DNA binding and exert antimutagenic activity for some carcinogenic heterocyclic amines and aflatoxins. In the present experiment, the possible inhibitory effects of chlorophyllin on 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) carcinogenicity were investigated. Female F344 rats were administered both PhIP, 0.02% in the diet, and chlorophyllin, 1%, in the diet (group 1), or either PhIP (group 2) or chlorophyllin (group 3) alone for 54 weeks. The incidence of mammary adenocarcinomas induced by PhIP was reduced by chlorophyllin co-administration from 40% (8/20 rats) to 15% (3/20). While the difference was not statistically significant, the multiplicity of adenocarcinomas was significantly (P < 0.05) reduced by chlorophyllin co-administration from 0.50 per animal to 0.15. On the other hand, incidence of colon adenomas was slightly, but not significantly, increased from 10% to 20%. Neither mammary nor colon adenocarcinomas were observed in group 3. Thus, chlorophyllin reduced PhIP mammary carcinogenesis, suggesting that chlorophyllin is an effective chemopreventor when ingested simultaneously with the carcinogen.

Organ-dependent modifying effects of caffeine, and two naturally occurring antioxidants alpha-tocopherol and n-tritriacontane-16,18-dione, on 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced mammary and colonic carcinogenesis in female F344 rats.

Modifying effects of caffeine, alpha-tocopherol, and n-tritriacontane-16,18-dione (TTAD) on 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP)-induced mammary and colonic carcinogenesis were investigated in female F344 rats. Groups of 20 rats, 6 weeks old, were given 0.02% PhIP (in diet) alone, or together with 0.1% caffeine (in drinking water), 0.5% alpha-tocopherol (in diet) or 0.1% TTAD (in diet) for up to 54 weeks. Groups of 10 females receiving basal diet or one of the test chemicals without PhIP supplementation were also maintained. The final combined incidences (adenomas plus adenocarcinomas) and multiplicity (No./rat) of mammary adenomas and adenocarcinomas were significantly lowered in the PhIP plus caffeine group (10%, 0.10) as compared to the PhIP alone value (40%, (1.50). Incidences of mammary tumors in the PhIP plus alpha-tocopherol or TTAD groups tended to be decreased while their multiplicities were significantly lowered. With regard to colon tumor development, on the other hand, rats given PhIP plus caffeine exhibited an elevated incidence (75% versus 15% in the control), whereas alpha-tocopherol and TTAD had no effect. Surprisingly, metabolic activation of PhIP was inhibited by addition of caffeine in an in vitro assay. The results indicate that caffeine exerts a potent chemopreventive action against PhIP-induced mammary carcinogenesis, but acts as a co-carcinogen for PhIP-induced colonic carcinogenesis.